addictions symposium Flashcards
tolerance
reduced responsiveness to a drug caused by previous administration
develops in response to many types of drug and an example homeostasis
dispositional tolerance
less drug reaches receptor
mechanisms: less drug absorbed, drug metabolised faster, more drug excreted
pharmacodynamic tolerance
drug has less action at the active site (receptor)
mechanisms: fewer drug receptors, less efficient drug receptors
mechanisms of dispositional tolerance
decreased rate of absorption
inc rate metabolism to inactive metabolites
decreased rate of metabolism to active metabolites
increased rate of excretion
mechanisms of pharmacodynamic tolerance
down regulation or internalisation of drug receptors
reduced signalling down stream of drug receptors
some other compensatory mechanism
development of tolerance may also lead to…
withdrawal symptoms
how may development of tolerance lead to physical dependence
in order to avoid the (unwelcome) withdrawal effects
reward pathyway
neurones project from ventral tegmental area to nucleus accumbens and prefrontal cortex
when VTA neurones are stimulated dopamine is released causing a sensation of pleasure/reward
how is reward pathway normally activated
eating, drinking, sex
encourages healthy behaviours that lead to propagation of genes
what produces psychological component of addiction - craving
some drugs tap into reward pathway and increase dopamine levels
e.g. heroin, cocaine, alcohol
issues of risk and drug misuse
type of drug and effects - overdose, mental health purity, dose, strength, tolerance (lack quality control) route of administration legal status comorbid health conditions likelihood of dependency method of purchase drug related deaths
stimulant drugs
cocaine
amphetamine
metamphetamine
methylphenidate
what is cocaine
monoamine reuptake inhibitor - dopamine, serotonin, noradrenaline increase
esp dopamine
effects of cocaine
stimulant and euphoriant anaesthetic effect hypersensitivity (light, noise) inc alertness + energy inc confidence, impaired judgement lessens appetite + desire for sleep
risks with cocaine
damage to nose + airways convulsions with resp failure cardiac arrhythmia's + MI htn and CVA toxic confusion paranoid psychosis
